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356                                                RORQUALS                                              CHAFi

symphysis of the jaws to the middle of the belly is, as in other
species, marked by furrows, forty to fifty-eight in number. The
hairy covering is reduced (in an adult female) to thirteen hairs
on each side of the lower jaw ; in a foetus there were also seven
hairs on each side of the npper jaw, as well as rather more on
the lower jaw — altogether, forty-eight. This Whale appears to
feed chiefly upon small Crustacea, especially the Copepod, Oalanns
finmarcliiGus* The number of baleen plates is about 330 on each
side of the jaw. This Whale sometimes swims singly, but usually
in schools of even as many as fifty.

Hudolphi's Korqual (B. ~boreculis) seems to be a perfectly
inoffensive beast ; it is said to be able to stay under water for
as long a time as twelve hours.

A smaller species than the last is JB. rostrata — at the outside
33 feet in length. Here the hairy covering is reduced1 to "two
small hairs on the integument covering the apex of the lower
maxilla." The colour is greyish black above, the underside
white. On the other hand, B. sibbaldii, the Blue Whale, is the
giant of its race, reaching a length of 85 feet. Its colour is a
dark bluish grey, with small whitish spots on the breast. The
dorsal fin is small and low with straight margins.

j?. musculus, the Finner, is intermediate in size — not more
than 70 feet. It seems doubtful whether the " sulphur bottom./*
& awŁtralis, of Antarctica and JB. jpatachonica differ specifically
from this.2

The genus Megaptera is very near JBalaenoptera, but differs
from it mainly in the following external and internal characters.
The dorsal fin is not very prominent, and its place is taken by a
lowish hump, whence, indeed, the common name of this Whale,
" Humpback." The pectoral fin is unusually long, and the
creature uses it to beat itself, the surrounding water, and, more
playfully, its mates. The general outline of this Cetacean is
more clumsy than that of Balaenoptera. The most important
internal difference is in the form of the scapula, which has at
most a slight acromion and coracoid process. These are rather
more pronounced, according to Messrs, van Beneden and Gervais,3

* Notts on the Anatomy oflfl rostrata," Proc, Zool. Sfoc. 1870, p. 805.
3 vpn, H&ast, "Notes on a Skeleton of Bcda&wpterm australis,** Proc. Zool. Ł®ts.
8S, p. '5dSL
8 0*t*)ffnqpkSe «fa» (Mads, Pam, 1880, p. ISO.